From a410f0cb75b0c58a1baa7f721c13db67a9c1e755 Mon Sep 17 00:00:00 2001
From: Lars <larsh@apache.org>
Date: Sun, 22 Sep 2024 17:48:42 -0700
Subject: [PATCH] Fix metadata reflection for DECIMAL columns

---
 .../org/duckdb/DuckDBDatabaseMetaData.java    |  4 +-
 src/test/java/org/duckdb/TestDuckDBJDBC.java  | 54 ++++++++++++++++---
 2 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java b/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java
index 7074b0ca..12bfe16a 100644
--- a/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java
+++ b/src/main/java/org/duckdb/DuckDBDatabaseMetaData.java
@@ -878,8 +878,8 @@ public ResultSet getColumns(String catalogPattern, String schemaPattern, String
                                   + "column_name as 'COLUMN_NAME', " +
                                   makeDataMap("regexp_replace(c.data_type, '\\(.*\\)', '')", "DATA_TYPE") + ", "
                                   + "c.data_type AS 'TYPE_NAME', "
-                                  + "NULL AS 'COLUMN_SIZE', NULL AS 'BUFFER_LENGTH', "
-                                  + "numeric_precision AS 'DECIMAL_DIGITS', "
+                                  + "numeric_precision AS 'COLUMN_SIZE', NULL AS 'BUFFER_LENGTH', "
+                                  + "numeric_scale AS 'DECIMAL_DIGITS', "
                                   + "10 AS 'NUM_PREC_RADIX', "
                                   + "CASE WHEN is_nullable = 'YES' THEN 1 else 0 END AS 'NULLABLE', "
                                   + "COLUMN_COMMENT as 'REMARKS', "
diff --git a/src/test/java/org/duckdb/TestDuckDBJDBC.java b/src/test/java/org/duckdb/TestDuckDBJDBC.java
index 6fc1907a..b0cbcfe1 100644
--- a/src/test/java/org/duckdb/TestDuckDBJDBC.java
+++ b/src/test/java/org/duckdb/TestDuckDBJDBC.java
@@ -1866,8 +1866,8 @@ public static void test_schema_reflection() throws Exception {
         assertEquals(rs.getInt(5), Types.INTEGER);
         assertEquals(rs.getString("TYPE_NAME"), "INTEGER");
         assertEquals(rs.getString(6), "INTEGER");
-        assertNull(rs.getObject("COLUMN_SIZE"));
-        assertNull(rs.getObject(7));
+        assertEquals(rs.getInt("COLUMN_SIZE"), 32); // this should 10 for INTEGER
+        assertEquals(rs.getInt(7), 32);
         assertNull(rs.getObject("BUFFER_LENGTH"));
         assertNull(rs.getObject(8));
 
@@ -1889,8 +1889,8 @@ public static void test_schema_reflection() throws Exception {
         assertEquals(rs.getInt(5), Types.INTEGER);
         assertEquals(rs.getString("TYPE_NAME"), "INTEGER");
         assertEquals(rs.getString(6), "INTEGER");
-        assertNull(rs.getObject("COLUMN_SIZE"));
-        assertNull(rs.getObject(7));
+        assertEquals(rs.getInt("COLUMN_SIZE"), 32);
+        assertEquals(rs.getInt(7), 32);
         assertNull(rs.getObject("BUFFER_LENGTH"));
         assertNull(rs.getObject(8));
         assertEquals(rs.getString("REMARKS"), "a column");
@@ -1911,8 +1911,8 @@ public static void test_schema_reflection() throws Exception {
         assertEquals(rs.getInt(5), Types.INTEGER);
         assertEquals(rs.getString("TYPE_NAME"), "INTEGER");
         assertEquals(rs.getString(6), "INTEGER");
-        assertNull(rs.getObject("COLUMN_SIZE"));
-        assertNull(rs.getObject(7));
+        assertEquals(rs.getInt("COLUMN_SIZE"), 32);
+        assertEquals(rs.getInt(7), 32);
         assertNull(rs.getObject("BUFFER_LENGTH"));
         assertNull(rs.getObject(8));
 
@@ -1933,6 +1933,48 @@ public static void test_schema_reflection() throws Exception {
         conn.close();
     }
 
+    public static void test_column_reflection() throws Exception {
+        Connection conn = DriverManager.getConnection(JDBC_URL);
+        Statement stmt = conn.createStatement();
+        stmt.execute("CREATE TABLE a (a DECIMAL(20,5), b CHAR(10), c VARCHAR(30), d LONG)");
+
+        DatabaseMetaData md = conn.getMetaData();
+        ResultSet rs;
+        rs = md.getColumns(null, null, "a", null);
+        assertTrue(rs.next());
+        assertEquals(rs.getString("TABLE_NAME"), "a");
+        assertEquals(rs.getString("COLUMN_NAME"), "a");
+        assertEquals(rs.getInt("DATA_TYPE"), Types.DECIMAL);
+        assertEquals(rs.getString("TYPE_NAME"), "DECIMAL(20,5)");
+        assertEquals(rs.getString(6), "DECIMAL(20,5)");
+        assertEquals(rs.getInt("COLUMN_SIZE"), 20);
+        assertEquals(rs.getInt("DECIMAL_DIGITS"), 5);
+
+        assertTrue(rs.next());
+        assertEquals(rs.getString("COLUMN_NAME"), "b");
+        assertEquals(rs.getInt("DATA_TYPE"), Types.VARCHAR);
+        assertEquals(rs.getString("TYPE_NAME"), "VARCHAR");
+        assertNull(rs.getObject("COLUMN_SIZE"));
+        assertNull(rs.getObject("DECIMAL_DIGITS"));
+
+        assertTrue(rs.next());
+        assertEquals(rs.getString("COLUMN_NAME"), "c");
+        assertEquals(rs.getInt("DATA_TYPE"), Types.VARCHAR);
+        assertEquals(rs.getString("TYPE_NAME"), "VARCHAR");
+        assertNull(rs.getObject("COLUMN_SIZE"));
+        assertNull(rs.getObject("DECIMAL_DIGITS"));
+
+        assertTrue(rs.next());
+        assertEquals(rs.getString("COLUMN_NAME"), "d");
+        assertEquals(rs.getInt("DATA_TYPE"), Types.BIGINT);
+        assertEquals(rs.getString("TYPE_NAME"), "BIGINT");
+        assertEquals(rs.getInt("COLUMN_SIZE"), 64); // should be 19
+        assertEquals(rs.getInt("DECIMAL_DIGITS"), 0);
+
+        rs.close();
+        conn.close();
+    }
+
     public static void test_time_tz() throws Exception {
         try (Connection conn = DriverManager.getConnection(JDBC_URL); Statement s = conn.createStatement()) {
             s.execute("set timezone = 'UTC'");